Mop



W. HASTINGS Nov. 20, 1962 MOP Original Filed Feb. 2, 1959 atent Ufifrce 3,364,295 Patented Nov. 20, 1962 3,064,295 Mor Whitney Hastings, Six Acres, Newfield, Middletown, Conn. Continuation of abandoned application Ser. No. 790,762,

Fe8li.32, 1959. This application Jan. 26, 1960, Ser. No.

4- Claims. c1. 15-147 This invention relates to mops, and in particular provides the art with a new and improved method of shaking mops and a new and improved mop especially adapted to be effectively shaken for removal of adherent materials with greatly increased efiiciency. This application is a continuation of my copending application Serial No. 790,762, filed February 2, 1959, now abandoned.

The old fashioned dust mop with which the art has been familiar for so many years has long been recognized to be most difficult to clean by shaking. Furthermore, to obtain such cleaning effect as is possible by shaking, the mop head must be oscillated in a fairly large arc, or the mop handle above the mop head must be pounded against a window sill or some other object. If it is desired to shake a mop out a window, the window must because of the large shaking are required be left quite far open, often undesirable, as in bad weather.

Recognizing these disadvantages of the usual dust mop, the art has in the past endeavored to provide improved shaking by use of various more or less complicated mechanisms; for example, devices producing whirling action in the mop head. However, even here efiective shaking action has not been as great as could be desired. That is, differential velocity between mop head and particles adherent thereto has been less than could be desired, with consequent proportionally less tendency for the inertia of small attached particles to be sufiicient to cause them to separate them selves from the mop head. Furthermore, these prior art devices have been expensive to manufacture, as well as relatively heavy and cumbersome.

It is the main object of the present invention to provide a mop which is not only simple, light, inexpensive and trouble-free, but which at the same time provides a greatly improved shaking action through increased inertial forces tending to drive adherent particles from the mop head. It is a further important object to provide such a mop in which the effective shaking action may be achieved even while shaking the mop while the mop head is out side a window and with the window almost closed. A further object is to provide such a mop which at the same time may be bent just above the mop head to facilitate mopping under furniture.

I have discovered that all these desirable objects may be very effectively accomplished by means of structure which appears deceptively simple in retrospect, though involving a concept and approach altogether new despite the antiquity of the problem.

I have discovered that if a spring of suitable character is interposed between mop head and mop handle, it is possible to obtain a mop in which a small force applied in resonance with the natural frequency of the system is capable of producing a periodic motion characterized by a whipping action with high rates of change in velocity, or acceleration, which removes dust with great effectiveness.

In addition to high accelerations, such a mop must have other qualities to perform satisfactorily. It must be neither too stiflf nor too flabby to handle easily, and the natural frequency of the spring system must be in the range of about 2 to 4 /2 complete cycles per second, in .order that a small external force can be applied to a mop handle at a resonant rate without strain or discomfort.

I have found how all these qualities (high acceleration, desirable springy feel, and suitable natural frequency) may be simultaneously and simply achieved. Letting:

n=frequency (complete cycles per second);

T=time required for one complete cycle (seconds);

W=weight of complete mop head (pounds);

k=the spring constant: the weight required to produce 1 foot deflection in spring end with mop handle horizontal and mop at rest (pounds/foot);

g=acceleration of gravity (ft./sec./sec.);

A=amplitude of each vibration or swing of the mop head (feet);

x=the distance of the mop head from equilibrium position at any particular time (feet); maximum 2: for any given vibrational pattern=A; and

d droop of mop head below horizontal (measured at junction with spring, when the mop handle is held horizontal and the mop is at rest) (feet);

then the following equations are applicable with practical accuracy:

W Ta 1 is *r new a=41r n x and It will thus be seen, from Equation 2, that frequency is directly proportional to the square root of the spring constant k and inversely proportional to the square root of the weight of the mop head W. From Equation 3, it is seen that the frequency is also directly proportional to the square root of the acceleration. Furthermore, as shown by Equation 4, the spring constant k is equal to the weight of the mop head divided by the droop below horizontal caused thereby when the mop handle is held horizontally. This means that the frequency is inversely propertional to the square root of the droop, wholly Without reference to the weight of the specific mop head, according to the following equation:

Thus, I have discovered that, for practical purposes, not only frequency but also acceleration at any given point depend on droop as above defined. Furthermore, the quality of springy feel without excess stiifness or flabbiness is also directly controlled by d, since that quantity varies inversely with increased stiffness of the spring. Finally, d provides the only measure needed of spring length, since the amount of droop increases directly with the length of the spring for any given leaf or other springy material. Thus, if spring length is increased, the stiffness of the spring per unit of length must be increased to produce the same droop.

V l have discovered that if d is made to be in the range of /2" to 2 /2", all these important qualities and objects are achieved. So far as I am aware, my discovery is wholly without precedent or foreshadowing in the art.

Other objects, advantages and features Will appear from the following description taken together with the attached drawings of presently preferred embodiments of the invention, in which:

FIG. 1 is a plan view of the presently preferred embodiment of the invention, with the handle partially broken away;

FIG. 2 is a side elevation of the mop of FIG. 1, with the handle brokenaway, and showing in dotted lines various positions of the spring and mop head during shaking;

FIG. 3 is a detailed view corresponding to FIG. 2 and showing in more detail the manner in which the spring is assembled to the remaining parts in the preferred embodiment;

FIG. 4 is a plan view of a modified embodiment of the invention, with the handle broken away;

FIG. 5 is a sectional view taken at 55 of FIG. 4, with both the main handle and the spring broken away; and

FIG. 6 is a sectional view taken at 66 of FIG. 5.

Referring now in more detail to the drawings, there is shown in FIGS. 1 and 2 a mop indicated generally at 10.

The mop 10 includes a wooden handle 12, a laminated flat spring 14 secured therein, and a mop head 16 secured to the outer end of the flat spring 14. As is shown in more detail in FIG. 3, the laminated flat spring 14 comprises three layers 14a, 14b and 140 of resilient metal, such as steel. As also shown in more detail in FIG. 3, said lamiuations 14a, 14b and 140 may suitably extend into a fitting slot cut in the end of the handle 12, and be secured in said handle by fasteners 18 extending therethrough and anchored therein. If desired, the holes in the laminations through which the fasteners 18 extend may be elongated axially of the handle to facilitate slipping of said leaves relative to one another during shaking. At the outer ends of said laminations the same are secured together by a bolt 20 extending through mating holes (which may also if desired be longitudinally elongated) toward the outer ends of said laminations, said bolt passing also through mating holes ina U-shaped member 22, the closed end 7 of which extends below the laminations to accept the frame 24 of the mop head.

The frame 24, which is pivotally seated within the member 22, provides support for a dust mop head of conventional character including yarns 26 secured to a canvas portion 28 having in its upper surface an opening defined by the braid 30, through which opening the frame 24 may be removably inserted.

In the embodiment described, each spring lamination is ,6, thick; the spring length is 8" and width the complete mop head with frame 24 weights 9 /2 ounces; droop of the mop head (at junction with spring end) when the mop handle is held horizontal is about 1 inch; and the natural frequency is slightly in excess of 3 complete shaking cycles per second. I

In operation, the mop handle 12 is grasped toward the free end thereof with one hand and toward the spring end thereof with the other hand. By giving the handle an oscillating movement with one or both hands, the mop head 16 maybe given an oscillating motion of greater amplitude, the axis of the spring moving in a plane perpendicular to the planes defined by the surfaces of said larninations. All points in the mop head and spring of course move either in this plane or in a planerparallel thereto. In this embodiment, not only do the mop head and spring oscillate more easily in these planes than in any other, but indeed these are the only planes in which in this embodiment oscillationcan be achieved at all as a practical matter. It will be found that it is possible to achieve in this way a quite extensive whipping action, so that at the extremes of oscillation the mop head changes from a very substantial velocity in one direction to a very substantial velocity in the directly opposed direction in a very small interval of time, with the result that momentary differential velocities between mop head and adherent particles, and consequent inertial separating forces, are

7 7 extremely high.

In FIGS. 4, 5' and 6 are shown a modification of the invention, in which instead of a laminated spring there is used a spring comprising four metal wires 114a, 114b, 1140 and 114d, each approximately A in diameter. These wires are inwardly concavely curved while, however, at the same time all their axes are in substantially the'same plane. The curvature of the axes of the wires 114a through 114d in said plane produces what is effectively, and is referred to herein as, a single spring (14 inches long) of very great width( 6%) and relatively little thickness, whereby oscillation of points in said spring and the wires comprising the same, as well as points in the mop head 116, occurs only in planes substantially perpendicular to the plane defined by the axes of said wires, there being substantially more resistance to deformation pursuant to forces in torque, as well as bending forces in planes other than those referred to. In this embodiment droop is 1%" and frequency is about 2 /3 cycles per second.

Actually, in the embodiment shown, the Wire 1114a is integral with the wire 114d and the wire 11412 is integral with the wire 114e, the wires being held together by clamp 124, in which is also held the frame of the mop head 116. Near the inner efiective spring extremity, the Wires 114a through 114d are held together in substantially a single plane thereat by clamp member 140, as shown in more detail in FIG. 6. Also secured by the clamping member 149 and extending together with the ends of the other four Wires through the grip 142 (in which they may be force fitted or otherwise secured) into the han dle 112, in which they are secured by force fitting or otherwise, is wire 141.

The modified embodiment just described may be operated in the same general manner as the laminated spring embodiment first described with both hands holding the handle 112. I

Or, if preferred, one hand mayhold the handle 112 and the other hand the grip 142. It is possible in this manner, by development ofproper (resonant) timing, to produce wide and violently whipping swings of the mop head without moving either hand to any great degree. It

is largely a matter of timing; that is, giving to one hand through a window which is only slightly open, the small movements within the open window space producing very wide movements with sharp whipping action in the mop head outside.

Other embodiments within the spirit and scope of this invention will readily occur to those understanding the above disclosure. For example, many different types of springs may suitably be used between the handle and the V mop head. What is essential is that there be, between the handle and the mop head and secured to each, a spring portion which is (1) more flexible than the handle, 7

(2) resilient so as to return to an unstressed position from a stressed position, and (3) provides a droop of /2" to 2.5". The spring portion should be of configuration such that during oscillatory motion in use, said spring portion is more easily moved, within itself, in one set of parallel planes than in any other. That is, in use there is inherent within the spring portion itself a substantially greater resistance to any deformation pursuant to torque forces than to deformation in the oscillatory planes. Without such greater resistance to forces in torque, as where an ordinary coil spring for example is used, there is a dissipation of energy and disorganization of direction of mop head movement which detracts from crisp whipping action.

What is claimed is:

1. A mop comprising a handle, a mop head, and mop head-carrying spring means interposed between and connected to said handle and said mop head for eifectively removing dust from said mop head when said mop is shaken, said means comprising a spring of a fixed length and being free to vibrate over its length between said handle and said mop head and being of a character such that said head droops from /2" to 2%" below said handle when the mop is held at rest with the handle portion horizontal and, when a small periodic force is applied to said handle at a frequency corresponding to the natural frequency of said head-carrying spring means an oscillatory whipping action having high rates of change in velocity is imparted to said head in a range of from 2 to 4 /2 complete cycles per second.

2. The mop of claim 1 in which said spring is of a configuration to vibrate more easily in one direction than in any other.

3. The mop of claim 1 in which said spring is greater in width than in thickness.

4. The mop of claim 1 in which said spring comprises a plurality of thin wide strips of resilient material laminated together.

References Cited in the file of this patent UNITED STATES PATENTS 655,369 Price Aug. 7, 1900 1,795,651 Hunter Mar. 10, 1931 1,821,481 Schempp Sept. 1, 1931 2,755,697 Miessner July 24, 1956 2,929,087 Salmon Mar. 22, 1960 FOREIGN PATENTS 272,533 Switzerland June 1, 1951 624,392 Great Britain June 7, 1949 1,056,318 France Oct. 21, 1953 

